DESCRIPTION (Directly taken from the application) The Data Coordinating Center (DCC) for the Mortality and Morbidity Among Hemodialysis Patients (MMHD) Full-Scale Study will coordinate the scientific and operational aspects of the Study. This randomized clinical trial will evaluate two aspects of delivering hemodialysis: a low vs. high KT/V and a low flux/bio-incompatible vs. high flux/biocompatible membrane (in a two-by-two factorial design). The effectiveness and safety of these factors in reducing the mortality and morbidity of hemodialysis patients will be studied. In the beginning months of the initial Recruitment and Follow-Up Phase (Phase I), the DCC, in conjunction with the Steering Committee, will review the results of the Pilot Study and finalize the design and protocol for the Full-Scale Study. Review and finalization of the Manual of Operations and data forms will take place. The database management system (using Oracle) that we established in the Pilot Study will be revised as necessary to carry out the Full-Scale Study. The randomization schedule for entering patients will be generated. The DCC will provide central training of Clinical Center staff in the areas of entry and follow-up of study subjects, completion of study forms, and use of the distributed data entry system. The Nutrition Consultant Group will provide the training and ongoing evaluation of dietary data and the Health Status and Comorbidity Assessment Group will do the same for these data. Dr. Chumlea will provide training and monitoring of anthropometry data. The DCC will arrange meetings of the Steering Committee and participate in these meetings and report the proceedings. The database management system will be used to assure accurate and complete collection of Study data. A query system will be used to resolve data discrepancies. A major function of the DCC during the Recruitment and Follow-Up phases (Phases I and II) will be to monitor patient recruitment and compliance to the protocol as a whole and by Clinical Center. Study progress will be reported in monthly reports to the Clinical Centers, newsletters, and in presentations to the Steering Committee and External Advisory Committee. Statistical analyses will be performed during the course of the study with final analyses completed and reported during Phase III of the Study. The DCC will develop new statistical methodology, as needed, to properly analyze the data being collected. Since the Study is a multi-centered effort, including several organizational Components, the DCC will be proactive and work to foster a spirit of cooperation so that goals of the Study are met.